Our laboratory focus is to reveal functional mechanisms of integral membrane proteins at the level of chemistry and atomic structure for impact on drug design. Membrane proteins include bacteriorhodopsin, ATcase-bacteriorhodopsin fusion protein, nicotinic acetylcholine receptor, serotonin receptor, thrombin receptor, a NNa+/K= ATPase, and CHIP 28. Soluble proteins include thymidilate synthetase, creatine kinase, colicin, d-UMP hydroxymethylase, SIV/HIV protease, HIV integrase, B. thuringiensis toxins (Cry2a, Cry1c, Cyta), and a designed 4-helix bundle. Synthesized peptides include those used for antibody production, enzyme substrates and ligands, and peptide-based 'peptitergents' which assist in solubilization and crystallization of membrane proteins. Following isolation, expression or synthesis, these proteins and peptides will be purified and characterized prior to 3-D crystallization. To facilitate characterization and crystallization, mass spectrometry will be used to assay purity, mass, and post-translational processing events. In addition, these efforts will develop purification procedures of hydrophobic proteins and peptides in environments amenable for mass spectrometry.